[EE] PCB standoff
Mike Hord
affixed to a PCB
to provide a conductive threaded anchor and standoff. Soldered down is
okay,
swaged may be better. Should be small- 2 to 2.5mm threaded hole with an OD
as
small as possible.
Basically, I have a circuit board which will be inside a case and needs to
be mounted
to the case with about 2-4mm standoff. Screws can only come from outside;
access
on the inside is good enough to align the board to a hole but not good
enough to
allow a PTH/nut solution. Board is not thick enough to thread a PTH,
either.
Name for this part? Search terms? Companies that deal in such?
Mike H.
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Dwayne Reid
>I'm looking for a product (I'm reasonably sure it exists) which can
>be affixed to a PCB to provide a conductive threaded anchor and
>standoff. Soldered down is okay, swaged may be better. Should be
>small- 2 to 2.5mm threaded hole with an OD
>as small as possible.
Keystone makes swaged standoffs - we use larger parts than you
describe but they *may* have smaller.
The ones that we use are large: 0.25" diameter, 0.25" tall, 6-32
thread, swage portion extends above the 0.25" standoff height and is
3/16" diameter. In other words, they mount in a 3/16" plated-through
hole in the PCB.
The ones that we purchase are plated brass and solder readily if
needed for current-carrying applications.
dwayne
--
Dwayne Reid <dwa...@planet.eon.net>
Trinity Electronics Systems Ltd Edmonton, AB, CANADA
(780) 489-3199 voice (780) 487-6397 fax
www.trinity-electronics.com
Custom Electronics Design and Manufacturing
RussellMc
affixed to a PCB to provide a conductive threaded anchor and standoff.
Soldered down is
okay, swaged may be better. Should be small- 2 to 2.5mm threaded hole with
an OD
as small as possible.
________
Your description doesn't seem to exclude the following as a possible
possibility.
As the nuts or threaded towers below are between the PCB and case and as any
screw and 'nut' tightening happens prior to PCB insertion it seems to fit
inside rule set.
But, my parser may be broken :-).
World / Case // tower ( out-side / PCB / in-side )
1. Is there enough room on the non-case side ("in-side") of the PCB for a
screw head, with screw facing through PCB towards wall.?
This would allow you to insert a screw from the in-side through the PCB into
a threaded tower on the PCB out-side.
The tower either has a thread protruding from the out-side to pass through
hole in case (may or may not violate the "screws can only come from outside"
spec) OR has a threaded hole. ie standoff notionally could be a 4mm long
tube with a say 2mm internal threaded hold right through it. A 2mm flat
headed screw enters its in-side through the PCB and another threaded screw
enters its out-side via the case.
Biggest issues seem to be
- Total thread length inside rod for threaded portions of two
counter-inserted screws is 4mm.
- Screw head on far side of PCB needs to be low enough to not annoy.
2. The super enthused extend thread length by using a hollow screw
inserted through the PCB.
Screw through PCB from in-side and add a nut (or towerlet) on out-side BUT
screw is hollow and threaded to form a tower for an external screw to thread
into. Tower width this way is somewhat larger than other ways.
*Could be achieved by drilling and tapping COTS screws with a smaller
internal hole. *
3. Is an adhesive based solution (at PCB end) tenable? Conductive
requirement makes that harder.
Russell McMahon
Sean Breheny
what you are talking about. Also, PennEngineering makes broaching
fasteners for PCBs as well as SMD fasteners.
Sean
Mike Hord
redesign and the case involved is cast, I can add holes or remove
material but not add material. That is a problem, too.
Dwayne's product is pretty much exactly what I need albeit larger
than I'd really like.
Adhesives MAY be acceptable but reliability issues may preclude that.
Mike H.
Mark Rages
> Wurth Electronics makes press-fit "bushes" for PCBs which sound like
> what you are talking about. Also, PennEngineering makes broaching
> fasteners for PCBs as well as SMD fasteners.
>
> Sean
>
Yes, look at PennEng's KSSB:
http://www.pemnet.com/fastening_products/prod_desc.php3?cat=Fasteners+for+PC+Boards
--
Mark Rages, Engineer
Midwest Telecine LLC
mark...@midwesttelecine.com
RussellMc
Do you mean "no access after PCB installation" or "no access even during
manufacture" ?
My screws are assembly time items, so go on the board with everything else.
> since this is a redesign
If the redesign does not include a new PCB then I can understand the screw
prohibition.
If there are new PCBs made I assume it means that the system is so packed
that there is no room for a screwhead that is wider than a tower. Head
height is presumably not the issue?
R
PICdude
a relatively large OD. Not at the office today, so I don't have the
specifics with me now.
Another option you may look into is rivet nut (or "rivnuts" as I've
always known them). You can "rivet" these threaded nuts from the
underside, and screw a standoff etc into them...
http://www.mcmaster.com/#aluminum-rivet-nuts/=7hmzjf
Harbor Freight should have a lower-cost kit of these too.
Cheers,
-Neil.
Mike Hord
should not
post them so that sort of creates an impasse.
I will say this- the system IS packed, there is very little room for a
screw,
and even if there were room for it, there'd be other stuff in the way to
interfere
with turning it.
Mike H.
Jean-Paul Louis
look at PEM devices, there are several that can be pressed into the PCB and are standoffs
web site is
http://pemnet.com/fastening_products/prod_desc.php3?cat=Fasteners+for+PC+Boards
Hope that helps,
Jean-Paul
At 08:34 AM 6/11/2010, Mike Hord wrote:
> I'm looking for a
product (I'm reasonably sure it exists) which can be affixed to a PCB to
provide a conductive threaded anchor and standoff. Soldered down is
okay, swaged may be better. Should be small- 2 to 2.5mm threaded hole
with an OD
> as small as possible.
Keystone makes swaged
standoffs - we use larger parts than you describe but they *may* have
smaller.
The ones that we use are large: 0.25" diameter, 0.25"
tall, 6-32 thread, swage portion extends above the 0.25" standoff height
and is 3/16" diameter. In other words, they mount in a 3/16"
plated-through hole in the PCB.
The ones that we purchase are
plated brass and solder readily if needed for current-carrying
applications.
dwayne
-- Dwayne Reid <dwa...@planet.eon.net>
Trinity
Electronics Systems Ltd Edmonton, AB, CANADA
(780) 489-3199
voice (780) 487-6397 fax
www.trinity-electronics.com
Custom
Electronics Design and Manufacturing